Coin control circuit



July 22, 1941- s. w. ALLISON ETAL COIN CONTROL CIRCUIT Filed Sept. 29 1939 a Sheets-Sheet 1 S. WALL/SON lNl/ENTORS. J. 8.Mc A?! 7'. DJFOB 8V y 1941- s. w. ALLISON E 2,250,173

COIN CONTROL CIRCUIT Filed Sept. 29, 1959 s Sheets-Sheet 2 SENSITIVE RETURN 3g awn/sou /,v l/EA/ TORS: J. a m KIM ranoaa A TTORNEY July-22, 1941; s; w. ALLISON ETAL COIN CONTROL CIRCUIT 5 Sheets-Sheef 3 Filed Sept. 29, 1939 S. MALL/SON INVENTORS I J.8.Mc KIM A TTORNE V Patented July 22, 1941 UNITED STTES PATENT FFiCE.

COIN CONTROL CIRCUIT Sewell W. Allison, West Orange, N. J., James B.

McKim, New York, N. Y., and Theodore D.. Robb, Ridgefield, N. J., assignors to Bell Telephone Laboratories, Incorporated, New York, N. Y., a corporation of New York Application September 29, 1939, Serial No. 297,096

3 Slaims.

This invention relates to telephone systems and more particularly to toll switching systems.

Circuit arrangements for telephone switchboard operators positions are known which provide a common coin collect and refund key per position in substitution for individual coin disposal keys per trunk or cord circuit, which common coin disposal keys are selectively associated with any trunk or cord circuit at the position by the simultaneous operation therewith of a talk key individual to the desired trunk or cord. At switchboards so arranged, however, if the operators telephone set is connected to a particular cord and she desires to dispose of a coin over a line with which another cord in her position is connected, it is necessary for her to first disconnect her telephone set from the cord to which it may be connected, after which she operates the common coin key and the listening or talk key of the cord over which she desires to exercise coin control. Such an arrangement, however, may at times be objectionable as the operator is either obliged to delay disposal of a desired coin or, on the other hand, interrupt a conversation with a subscriber or distant operator.

An object of the invention, therefore, is to provide an arrangement whereby a common coin control unit may be operatively associated with any cord at an operators position and coin control potential transmitted thereover without interfering with the connection of the operator's telephone set to the same or any other cord or trunk circuit at the position. v

A feature of the invention resides in a circuit arrangement for telephone switchboards, having a coin collect key and a coin return key common to all the cords at an operators position and the usual talk and ringing keys individual to the several 'cords thereat, whereby a momentary ing key is associated, regardless of the condition of any talk key at the position.

Other features of the invention will appear from the following description and appended claims.

The invention will be understood from the following description when read in connection with the accompanying drawings Fig. l of which shows an incoming trunk line over which a calling subscribers line is extended;

Fig. 2 shows a cord and position circuit arranged in accordance with the present invention to collect coins on either end thereof; and

Fig. 3 represents a two-way ring-down toll line which is shown for the purpose of completing an operative disclosure of the cord circuit of Fig. 2.

Describing the operation of the circuit of the invention, it will be assumed that aloop closure is effected at a calling subscribers station over line TL thereby causing the operation of relay l. Relay l in operating closes an obvious circuit to operate relay 2 and by breaking its back contact, opens the low resistance winding of sleeve relay 3, thereby increasing the resistance of the sleeve circuit to a relatively high value. Relay 2 in operating closes an obvious circuit to light the line lamp 4.

Upon noting the lighted line lamp 4, the operator inserts plug 5 of the cord circuit in jack 6 of the calling line thereby operating sleeve relay '3 in a circuit which may be traced from ground,

upper high resistance winding of relay 3, sleeve of jack 6, sleeve of plug 5, supervisory lamp 1,

and resistance 8 to battery and ground. The operation of relay 3 opens its lower back contact to extinguish line lamp 4 and by closing its inner upper front contact provides a holding path for relay 2 whereby this relay is held operated as long as plug-5 remains in jack 6. Further, operation of relay 3 by closing its uppermost front contact prepares a circuit to operate relay 9 which circuit is completed when the ring spring of plug 5 meets the ring spring of jack 6, and the talking key of the cord circuit is operated, which circuit closure will be later described, it being assumed that the call was answered before the operators talk key It was operated. When the operator actuates talk key It, the following circuit operations take place. Closure of contacts l I completes a circuit to operate relay l2 which can be traced from ground, contacts E3 of relay l4, conductor l5, contacts H of key It and upper winding of relay l2 to battery. Relay [2 in operating closes its contacts I6, ll, l8 and 19 thereby extending the tip and ring conductors'of the cord into the position circuit. Contact '20 is also closed which provides a locking circuit for relay l2 which can be traced from contact 2| of key I0, contacts 29 of relay l2 and lower winding thereof to battery. Closure of contact 22 of relay l2 closes a path in parallel with the above traced locking circuit which extends to and operates relay ld. The operation of relay I4 extends its operating ground through the winding of relay 23 to battery which relay in operating performs no useful function at this time. Operation of relay M by closing its contacts 24 causes the operation of relay 25 which circuit can be traced from ground, contacts 24, conductor 26, contacts 21 of relay 28 and winding of relay 25 to battery. Relay 25 in operating disconnects at its upper and lower contacts battery and ground from the tip and ring conductors of the cord and by closing its contacts 29 connects the busy test relay 39 to the tip conductor of the cord in a circuit .which can betraced over contacts 3| of relay 28, contacts 29 of relay 25, conductor 56 and contacts I! of relay l2 to the tip conductor of the cord, Returning now to the operation of relay l2, it will be noted that ground over contacts 2| of talk key l9, and contacts 23 of relay l2 also extends to the cord splitting relay 33 which relay in operating connects the sensitive relay 34 over conductor 35 to the sleeve of plug which is now in contact with the sleeve of jack 5. Due to the sensitive characteristics of relay 34-, this relay operates in series with the high resistance, upper winding, of relay 3, in the incoming trunk. Relay 34 in operating closes an obvious circuit to operate relay 36. Operation of relay 36 opens its contacts 31 thereby immediately releasing relay 38 in case this relay has started to operate in parallel with relay 25 from ground at contact 24 of relay M; It will now be noted that battery and ground over the inner upper and lower contacts of relay 38 is extended to the tip and ring of the cord and thence to the incoming line of Fig. 1 over conductors 39 and 4S and contacts l6 and I9 of relay l2. Due to the operation of relay |2 the battery which is supplied to the incoming line causes the operation of the plug seat relay 9 which circuit canbe traced from battery, lower contacts of relay 38, lower left winding of repeating coil 42, conductor 48, contacts l9 of relay I2, contacts 43 of relay 44, ring conduotons of plug 5, and jack 6, contacts 45 of relay 9 in the trunk, the winding thereof and contacts 45 of relay 3. Relay s'operates in this circuit and looks over a local circuit to RS-volt battery tery and ground'frorn the tip and ring or the line TL at'this point and. by closing its contacts 41 connects the ring conductor of the line through to the cord from which it receives battery supplied over the lower contacts of relay 38. Ground is'also'supplied to the tip conductor of the line over the inner upper contacts. of relay 38.

Upon learning the details of the desired connection, the operator touches the tip of plug 4| will not operate and upon receiving no busy indication in her telephone, the operator will proceed to extend the connection by inserting plug 4| in jack 55, which we have assumed is the line called, whereupon sleeve relay 5| of the line operates from ground through its upper high resistance winding, sleeve of the jack Eli and plug 4| to battery in series with supervisory lamp 52 and resistance 53.

Due to the fact that relay 33 is operated at this time, sensitive relay 54 is now connected over contacts 55 of relay 33 to the sleeve of the plug-4| and therefore this relay B. Operation of this relay (5) also removes batoperates in series with the high resistance winding of relay 5| in the line. Relay 54 in operating completes an obvious circuit to operate relay 28 which relay in operating opens at its contacts 21 the circuit for relay 25 which thereupon releases and connects battery and ground over its inner upper and lower contacts through the upper and lower windings of repeating coil 55 and conductors56 and 51 and contacts ll and ll! of relay |2 and contacts 48 and 56 of relay 49 to the line (Rig. 3) whereby a circuit is closed to operate the plug seat relay 58 in the line which circuit can be traced from. battery on the ring conductor of the cord and line, lower winding of retardation coil 59, lower winding of relay 6!], resistance lamp 6|, winding of relay 58 and upper contacts of relay 5| to ground. Relay 58 operates in this circuit and closes its upper inner contacts thereby completing a holding path for itself. Completion of this locking circuit also short-circuits the lower winding of relay 6!! which therefore does not operate at this time. Closure of the lower front contacts of relay 58 lights the busy lamp 62.

Ringing on the called line is accomplished by operating ring key 63 whereupon relay 49 operates in the following circuit, battery, upper winding of relay 49, contacts 64 of key 53, contacts 65 of ringing key 66, contacts 57 of relay 68, conductor 69, contacts 16 of relay 1|, conductor 12, contacts T3 of coin return key 74- and contacts 15 of coin collect key 15 to ground.

Operation of relay 49 operates relay 58 in the following circuit. Ground, contacts T1 of ringing key 63, contacts 18 of relay 49, conductor 19 and right-hand winding of relay 68 to battery. Relay 68 closes its contacts and opens its contacts 61 thereby completing a locking circuit for relay 49 which can be traced from battery, lower winding of relay 49, contacts 82 thereof, conductor 8|, contact 89 of relay t8, conductors 69, contacts it of relay H, conductors '22. contacts 13 of coin return key 1'4 and contacts 15 of coin collect key 16 to ground. Relay 68 in operating also closes its contacts 33 to operate relay 84, the circuit for which can be traced from battery, winding of relay 84, contacts 83 of relay 68, conductors 19, contacts 18 of relay 49 and contacts 71 of ringing key 63 to ground. Relay 68 by opening contacts 61 removes the ground from the lower armature of all the ringing keys at the position, thus making operation of a second key inefiective to operate its associated relay such as 44 or 49.

Relay 84 in operating closes its contacts 85 to complete an obvious locking circuit for relay 68. Operation of relay 84 also closes its contacts 8'! thereby connecting ground through resistance 88 to the tip and ring of the cord over contacts 89 of relay 99. From contacts 81 of relay 84 the path to the tip of the cord extends over contacts 9| of relay 58, upper left winding of repeating coil 92, conductor 93 and contact 35 of relay 49 to the tip of the plug 4| and line. The path to the ring of the line extends from contacts 81 of relay 84 over contacts 94 of relay 9!], contacts 95 of relay 68, lower left winding, of repeating coil 92, conductor 99 and contacts 9'! of relay 49 to the ring of the cord and line which ground causes ringing relay 60 in the line to operate over its lower winding to battery at the inner upper contacts of relay 53. Relay 6B in operating closes its lower front contacts to connect battery to the signal lead 98 which controls welleknown ringing equipment as indicated at the right-hand side of Fig. 3 which, however, forms no part of the present invention and therefore is not described. Relay 68 in opera-ting also causes the operation of relay 99, the circuit for which can be traced from battery, winding of relay 99, contact 89 of relay 68, conductor 69, contacts I9 of relay II, conductor I2, contacts 13 of coin return key I4 and contacts I5 of coin collect key I6 to ground. Relay 99 in operating closes an obvious circuit to operate relay 'II which relay in operating opens its contacts I9, following the closure of its contacts I99, whereby the ground at coin collect key I6 over conductor I2 is maintained on conductor 69, the new circuit passing over contacts I9I of relay 99 and contacts I99 of relay II. The operation of relay 99 also closes. its lowermost front contact to hold relay I4 operated. Release of ring key 63 releases relays 84 and 68 in turn. Relay 68 in releasing, releases relays 49 and 99 which in turn releases relay II. Release of relay 84 removes ground from the line thereby releasing relay 69 and disconnecting battery from the signal conductor 98.

Now that we have described how ringing on a line is controlled by the ringing key in a cord circuit, we will next describe how coin collect, or return, current can be applied to the line under control of the same ringing key. As we have assumed that the calling line of Fig. l is the extension of a coin subscribers line and that the subscriber has deposited a coin in the box at his station, the operator of course desires either to collect the coin, i. e. deposit it in the coin receptacle or to return the coin to the subscriber. We will first describe the coin collect operation in the case where the operator has not released the talking key and therefore relays I 2, I4, 23, 33, 34, 36, 54 and 28 in the cord are still operated and therefore the operators telephone is connected through repeating coils 42 and 55 to both ends of the cord and their associated lines.

In the event that the operator desires to collect a coin over line TL, she will first operate coin collect key I6 thereby operating relay I92 in a circuit which can be traced from ground over contacts 32 of key I6. Relay I92 in operating closes a circuit to operate relays I93 and 99 in series which circuit can be traced from battery, winding of relays 99 and I93, conductor I94, contacts I95 of key I6 and the lower contacts of relay I92 to ground. Relay I93 in closing its contacts I96 locks itself and relay 99 to ground over contacts I9 of relay II, contacts I99 of relay I4, contacts III] of relay 23 and the upper contacts of relay I92 to ground which holding ground is effective until the coin collect key I6 is released. Key I6, may, however, be released immediately whereupon relay I92 is released and the holding ground for relays I93 and 99 just traced is supplied to lead 69 from contacts I5 of key I6. Further relay I93 closes its left-hand contacts thereby connecting positive 110-volt direct current over left back contacts of relay I98 to contact spring II I of relay 84 in readiness to be extended to the line when relay 84 operates in response to a subsequent operation of a ringing key. Coin collect pilot lamp I9! is also lighted by closure of the outer right contact of relay I93. Operation of relay 99 opens its contacts 89 thereby disconnecting ringin ground and preventing ringing current from being connected to the line when a ringing key is subsequently operated as previously described. The cord position circuit is now in the coin control condition and ready for operation of a ringing key. As it is desired to collect a coin on line TL of Fig. 1, rear, or

answering, cord ringing key 66 will next be operated, whereupon relay 44 operates in a circuit from ground at coin collect key I6 and contacts I5 thereof, contacts I3 of key 14, conductor I2, contacts-I9 of relay II, conductor 69, contacts 61 of relay 68, contacts II 2 of key 66 and upper winding of relay 44 to battery. Relay 44 in operating closes its contacts I I3 thereby completing a circuit to operate relay 68 which can be traced from ground, contacts H4 of key 66, contacts II3 of relay 44 and the right-hand winding of relay 68 to battery. Relay 68 closes its contacts 89 and opens its contacts 61 thereby completing a locking circuit for relay 44 which can be traced from battery, lower winding of relay 44, contacts I I5 thereof and contacts 89 of relay 68 to ground at coin collect key 16 over conductor 69. Relay 98 in operating also closes its contacts 83 to opcrate relay 84, the circuit for which extends over contacts 83 of relay 68 and contacts II3 of relay 44 to ground at contacts II4 of ringing key 66. Relay 84 in operating closes its contacts 85 to complete an obvious locking circuit for relay 68 and by closing its contacts 86 and 8! extends the positive ll0-volt direct current standing on contact spring III, by virtue of operation of relay I93, to the tip and ring of the answering end of the cord circuit. The circuit for the tip conductor extending from positive ll0-volt battery, left contact of relay I93, left back contact of relay I98, contacts 86 and 8! of relay 84, contacts 9I of relay 68, upper left winding of repeating coil 92, contacts II6 of relay 44 to the tip of the plug 5 and thence over the line TL to the subscribers station, not shown, and the circuit to the ring conductor of the line extends from contact spring II I, over contacts 86 of relay 84, contacts I I! of relay 99, contacts of relay 68, lower left winding of repeating coil 92 and contacts H8 of relay 44 to the line. Operation of relay 68 also operates relay 99 which in turn operates relay II, relay 99 being energized over a circuit which includes contacts 89 of relay 68, conductor 69, contacts I9 of relay II and conductor I2 to ground at contacts I5 of collect key I6 now in its released condition. As long as key 66 is operated, relays I93, 99, 44, 68, 84, 99 and II remain operated and coin collect potential is applied to the line. When key 66 is released, relay 84 releases followed by relay 68 which in turn releases relays 44 and 99 which latter relay in releasing opens its contacts I9I thereby momentarily breaking the holding paths for relays I93 and 99 which immediately release, Relay 99 also releases relay II but this relay is slow torelease and does not close its contacts I9 to reconnect ground to conductor 69 until relays I93 and 99 have released.

In case the operator desires to return a coin at the calling station, the key I4 instead of key I6 will be operated, thereby causing the operation of relays I98 and 99 instead of I93 and 99, thereby connecting negative '-volt battery to the line when the key 66 is operated.

The transformer 92 is provided for the case where the line TL is a trunk which repeats coin potential toward the calling station and transmits a tone to the cord as an indication that the circuit is functioning properly. This tone is induced in the right-hand winding of the coil which is connected to the busy test conductor H9 which terminates, and is heard, in the operators telephone.

In case the talk key is released at the time a coin is collected or returned, relays I2, 33, I4,

23, 34, 54, 36, 28, 25 and38 are released and the operators telephone is disconnected from the cord. When the coin collect key 16, for example, is operated, relays-H32, I03 and 90 are operated as before and When the ring key 66 is operated, relays 54, 6B, 84, 99 and H are operated. In this case and in View ,of the fact that relays l4 and 23 are not operated, the operation of I02 supplies ground at its uppercontact over the normal contactsof relay 23 to hold relays I93 and 90 operated-in case the ringing key 68 is operated before the key It isreleased,

It; will be noted fromthe foregoing that op eration of a ringing key, either 66 or 63, provided a" coin key is not operated, causes ground to be connectedto the tip and ring of a connected line to initiate ringing thereon, whereas if a coin key is first operated, the position circuit is set in condition for coin control instead of ringing, the ringing ground being disconnected (at contacts 89 of relay 9E!) and a subsequent operation of the ringing key causes coin potential instead of ground to be connected to the associated line.

What is claimed is:

l. In-a telephone system, an operators position, a plurality of cord circuits thereat, a ringing key individual to each cord circuit, a coin control key common to said cord circuits, at source" of coin control current, and means responsive to operation of said coin control key and the subsequent operation of a ringing key to connect said source of coin control current to the cord With which the operated ringing key is associated.

2. In a telephone system, an operator's position, a plurality of cord circuits thereat, individual ringing keys for each cord a coin control key common to all the cords at the position, a source of coin control current, a source of ringing potential, means responsive to the operation of a ringing key to connect said source of ringing potential to the cord circuit associated with the ringing key, and means responsive to the operation of said coin control key and the subsequent operation of a ringing key to connect said source of coin control current to the cord associated with the ringing key to the exclusion from said cord of said source of ringing potential.

,3. In a telephone system, an operatorsposition, a plurality of cord circuits thereat, a source of ringing current, a ringing key individual to each cord circuit, relay means common to said position controlled by any of said ringing keys to connect said ringing potential to the cord with which the ringing key is associated and to disable all other ringing keys as long as the first key is operated, a source of coin control current, a coin control key common to said position, and means responsive to the operation of said coin control key and the subsequent operation of a ringing key to prevent connection of said source of ringing potential to any cord at the position and to connect said source of coin control current to the cord associated with the operated ringing key.

SEWELL W. ALLISON.

JAMES B. MCKIM. THEODORE D. ROBB. 

